SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa8d120747ffe9203b7d1bef13aedc2fcd000db88447498f261417e4b2fb71f4' 
  AND token = 'THMmv4xKzjHTiwAXeNv/M4CHPOGDYuDlMDRXXdtBiXo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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