SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dee8f64792a5697fa195160bdac9283f65bdb1057451d09876d9d31ca5466e46' 
  AND token = 'khqFldqOQsJ1TSOPyWeB/0r6CGKngQ/byImDfuMo0j8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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