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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c6896e96f9d0a551905c0053f9eac83b10137b4c05f1a4015ccd587cdbe9cbde' 
  AND token = '6lEyr9Q6X7cKlFVWt+9+0PkMGuTItlDC54nRT+1HD3c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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