SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '016f8b62dc384a33de2f22254f8e8ea830f3d7119051e129f7ee62532c53c996' 
  AND token = 'lPhqY+SdcB+sahNECR/Ocql6j9WDAArvWSe3+bRW1eg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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