SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7c82c93605f5593a5765f5363a57f6446e0486ea459ba403fa49c63946485ca' 
  AND token = 'WySeEHZetiaJOZ47jkbSomFViabYTYlObYZjbz9uGtc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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