SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '148550c3fc75d647193d0487e10be791007d19dfee897fd861db6aa3eb596939' 
  AND token = 'NE63uRA6BKvAmwSDXOG5iyouWDrZQ1ZM12uf1EuF+p0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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