SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96040bc8a8e5e43c43484dbd4684ac8b266df6838f3f31cb9d377346be26eb40' 
  AND token = '6UvbMsVcCzs/WziSmt7f0OPi1ewge59BsSKEkWR/VdY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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