SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b754533d7e01e252d8308da2f18468cb3491e671efc40cb0e1c4f1ae9e9da21' 
  AND token = 'NKptEMDLicq08paDsewS/yLjyWd4Y4JK07zC/kSKcDE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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