SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7fc2765786f11b78493d6d7bd2e45d9587af0016b4c3892b43c8f0b3e2c8fb59' 
  AND token = 'RKuuOcVFFHqSz7UfeoUkZxRX6Vl0HPmRWRYMUQEQ/Yk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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