SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '642a446a3367ea470491f6cd50e683a7f31f2fd2b0de80b3ab8d8567a9b7215e' 
  AND token = 'uMy/ivY7pFZWje+cQcOezUQ08aWz1gLH8r1bY85ps1o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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