SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8aa44cfa18a5841767ee9e5869082d918c431bee124906c4828196a787153b1c' 
  AND token = 'z0Us5BkJqWTlswdKPeCEy4viqKet2uywoBff3rxv9YQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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