SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd87f40427c546f29eae5f52490110865f2326965a29db5c32f136e4cf373b088' 
  AND token = 'TRgOK3AxdS6iVyvba3Ebr17etbCrz9hHhullH/StuKo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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