SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bc6e42fb734ef351a441ef92a120e61c0e3017cc4d8816a2b75b686a9d5c8b2' 
  AND token = 'IK4bJE6/q2gwcgngz3gvl9gTRLW1gKBHwYXxku3hUnQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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