SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48a0993d85ddecb6f4e6daa238416ddc4a6c56fc28a7a6da4b2bd61a8478d255' 
  AND token = '+WREmiR9fdw4pvt8o6HX4/T8zKcZ+xhei6Ue4orzzQE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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