SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f7d4b27da903d6335aea6da21aedc558f0413590c53b17957a369d4abb4890b' 
  AND token = '+GffycI6tXwKCguP2QeOvJsb4TW9D3bhuobOKeROHX8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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