SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '1a8e2a9dccf2440644bc159f3084e6cdf20877de9aaf36d594232ff2c97aadd8' 
  AND token = '/ITAz2VnNFCezbtFOitW7TwLzGZMViP9Ga+hn5Bqyow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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