SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6e55a6c246142f6e2dcb3980b5722dc1035f6d4b9485a13d771c84f368fd9dc' 
  AND token = 'vo2XYjtp4F6wkoPJENH/8xfws4TzzltnB1gU/ZLkCKE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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