SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ab3f7c1518b6ecc20aa8602452f949e485327ac212079533695177f2f84e010' 
  AND token = 'MEM0fSsNevoshuR4nTPQtidGE9nHsmKGSEpJ0xIJWs8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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