SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '64692df41a7fbf8b42838a39b271f2c83614cede49ded46327acfa81392453ea' 
  AND token = 'F17vuJr+uK/EwyFLoRJ+Ut0BdmM2hjopYUDt4+VvMto=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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