SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '519ca59eb160f2272894cdbca1cf226129fe008003dcf5c6f3175faf56c8b041' 
  AND token = '9Z/+qGFp8Fzpt7yWdhsVSsK+NEzB9qTsaJLTe3m4tAs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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