SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '31d80c3cbdc109e0bda96db3b99b18c6403bc30934cac3e0be8c82ff7f0b9950' 
  AND token = 'LBWGeo9aMgVDwVl+DKtNS88LE9g7GCay6Q6Wo4qyyuY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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