SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23d680047513fdecea86904c04539e51d4d0ffb0e37f6e817f0efd10db917188' 
  AND token = 'uKGA5oXVd+RlBHzMGKnFf8L4LfePLSiDC5RnJG1HRqc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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