SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9455f469cafd5290bd394d13874d94aa090844818e3eba8db0128a1ea051e82' 
  AND token = '+l6lqbNdUMJiHzH6vyrBOxafAHpoLRLTty/JNt1CZQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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