SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6588974b27ca7434c5f30ee5958fbd31770ee5f99e997b5c53ca28abfe56a481' 
  AND token = 'OWrfdQJldgWxEdW/aF8tt2FOjR8ZqxEbRF3DsN7bTu0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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