SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6dfdc293f8ba3b61bec61695652e626f06ba2c5ed663fcdf5ce39e0a54018707' 
  AND token = 'cgNaeiZcczSBwDAF9EPFPNmp5j37wz5Tj768wduDLW4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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