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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'a876b6adc9cfcbcc4ec9f8cae9122abe6090ac6e614c9a4cea2ab3fe6c20fdfd' 
  AND token = 'Qsjq7XwH4AmceUBhVhWciisghIG+1ruN0KCA0hsJgEE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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