SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca0cb54b0513a49bbd3b190492e649a3ea1c976a0b30de9aa620c6768dafeae5' 
  AND token = 'cC7bp1hEkpBzJgL4aJLY+ocXUqI8wo2xsIXrFYWjGJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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