SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8206f67a84f0c51cf7e2d3576aa8d562408bfd44c8f41efbd7ebad4a0ad21dae' 
  AND token = 'TTbi8B1nV+jMQ3YmLrif+hEvaf4dEqOAdMMNbxcWF1o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}