SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e818f25b7ec9552f5d8aee1ed4daf7bb58523d9f0959f2b647cf06ae6592a168' 
  AND token = 'AsHN4N0aQficdZRNdf1trvE2ezJYVoaWEZwOEj1D+xg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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