SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1879384802ef3e85b7c64ab0d311f9f5527a691b6334f1eaeb3ad305d2e9f0de' 
  AND token = '9h78wnAZRpBFLsLKWHggROZ+z5Cd9QI5sletTLGIAMU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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