SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac65df75cf5747617e95af2c3eb20aed72278c08805b2f40cade3a11846a8de6' 
  AND token = '0T+qm3KLwcARPRCIlIqYBgVb//VAYXXlvG9mZWBpCZE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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