SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12535518ed9e3ee7cf8a5eb838c76472b2df06132ae8af39ceb4559b877b3765' 
  AND token = 'eLbh8N1lRTx4idh5rhWhQHa3Z8hbsCUhc9MxWhbT7ak=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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