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SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '951a8b28d1ce123ecd3c5a2e7961922305bd7bbcc2141ec3f6defe5c59eed6ce' 
  AND token = 'FPrzm3kiqaYeWMyx7IpP+p9aTQhRAXalH6qh0EclpdE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}