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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f534cce838ced3fc2c1d688e384fde9444de3ee0cd88d2e5a79d27833f87d93a' 
  AND token = 'LyYp9qriP2VQrAObhTKOhQb1gBNowzUAx1aMjjg1JOU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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