SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ac32374473d4fefde1d25fbd25b1f60a6096683574d61232e317b209326105c5' 
  AND token = 'PKlC9u2jhkhA76xJysHBeEGihxAUG4ytme85bkkkzkE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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