SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '993ef5d0ac4c515332dcb69c2502f914ff0173add6f0aa70311f5fe57078e117' 
  AND token = 'Fo9gGtp/tiQPTDx/IJjzcDLWero0sqZtzc9hLwBaqKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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