SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '32a804de8b6d8c51fa289bef14db2213483407f383fa85b1999a864f70d24f66' 
  AND token = '44HOaLvBQvaDxxlUGYID05SpONnAuyB1XmA16vEYE0s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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