SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7393e19c0dfef27ef67a07bd8e4d9f24cb24967bee111ed0bd29a676e76f2b82' 
  AND token = 'NxaWYWQSDzhP9iTenJpwshZJldPHVnJrMQHL2CT+QAM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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