SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f30815d1310f83532cd66669f6609dcd566324521ab1836bf047feb128c28b54' 
  AND token = 'tymRwB1wZe8gucMrOGR3l1Di6om6a0xrPOALnKDcPqY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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