SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46e605d3fc9b405ef996ece0f39637f5b311af583af203f331547f7feca269f9' 
  AND token = 'Z9lFf8Vt8Vop1vjSVECE44ZvviQTy1IpO+yZR0aOiRQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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