SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be73567c0a12a0e435812c3625f9b3c3c15ad765795bfebfa64c924f6f3d48c2' 
  AND token = 'RRQmABzWnsF9hzqJQrkUfvvKsrOgNyYcG1nILaSkIew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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