SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ddb4da9e06e3461b1030d536792d601b4e5bd77e311ac492b71448fc97b88222' 
  AND token = 'wLH+JrAmeKlOrbHBx5oTrhMiQgpEJABERjkkgh7TeFA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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