SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70186f3d64e55873d5c326fc7d68f2e97be7e7b9911f458731e4c6412ca3cf20' 
  AND token = 'wfXDF2DCLa9ftK+JLFiPFxWLYCEDzPZhTu7X/c+Dqrw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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