SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'acd96638971c00514b3e520242f5f7e3ff334a23462b91c2ddbc54e59056f5db' 
  AND token = '6xeWiRD/7gf4wlNCvj2WmK4GyIlansETiAkv6PuB1/g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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