SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '302ee790d53eb415cd87ebfa1210393dd8fe72dff24fbd67edb6e9ace681d242' 
  AND token = 'Yea0UeRjtztzhRH2ifTm1RtL7YPKn05bbpQPBryF+N8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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