SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4227c08de4f214ea93bb687878a37c02629911a0825d1521357f977a70d143f' 
  AND token = 'RZ5DjQ39HMzdUvhpH5DgZ20OJl+aq5i6BzXBjVLZytU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}