SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '670973872b3c33246fabae847790debdab353d3fc32b48d60fd7ecdae28cfd14' 
  AND token = 'cowsP10o0YrshE9XrccW7X937OKlTHsYdInWEmaXbiA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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