SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45d2a2e652efff791a4c49e54747352853a7e2b50aea1ac2ff3c8e4658fdc580' 
  AND token = 'BQ9bsJFk4QU7HB+lHxf66FltKegJTUzqHEY8RdJG2PU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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