SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67b6dc4517f3e1a132d8e328cfd43f68c06e58ce5d424b878a19c2f2763aed25' 
  AND token = 'Ew5q/YTHsqHWgQFOcvAqf8b1ZmlD09/udjc+syI9lBY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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