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SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '51e3a16aedeed9ae9f7be56a18d26b5effe4b3aea6eed0e3f5f9a752f33b537c' 
  AND token = '7dzuGq0wd/AECzNyj04+BRqdkEhRC/YcajtKYWy27ZA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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