SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85a360d4acb0f1ee8281eebce3fc2eb7438fa8b878dd03e01c73422d89be7625' 
  AND token = 'bHfrNS2viSnyu/xVmTK4mkhwVMPJsVf3Zlsi/cjjESI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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