SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49a6eb4fabf592bbb180929a89d65e8e21b96ffcd8e3fc743800878e55eda5e8' 
  AND token = 'xiKBfOaxVuOXobNdrI5WONT5wG7cAInj+Fud7+vzLw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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