SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87e737d4ffc6168c0a5eb1083b647d0be9d7898ef085bfac9947623b7ed7b71a' 
  AND token = 'AFJ9arhsmrtA/g1OK6uALgwxxdQ3GCgLbg/z+rduq3Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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