SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c31a5d2d84bcaabe915c8c6e9bca5331fc9eb49576e17a5a5ee315851c23c65' 
  AND token = 'OlqTqki0biAbBWtprM6dVqQbLPa+ajLl5DEpV1OaIgE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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