SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '499217cd4952aee19db8b95c7b0a2573118a79fbefba59c768ba9642124518f9' 
  AND token = 'JVue5N4cM4NkY1ebKk4sdUwhgqx2dVEMYal2rO+Gw0g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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