SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9375eb2bb292921a3b422e902818c0183de272f6d6eb423dc6d80e51815f9af9' 
  AND token = 'MztCyBgkikXUIOZaJRLcptZL4/GXKd6GKJ5H7uEFMOI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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