SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '810d53e6bc2cbf81590a3487314dfacaa76870bec4d346b39cc20a0e3e6dcfcb' 
  AND token = 'LOKvH8dqZ/EmLOn4X9hBOHF85QKTf9I7rM8+uBYM2KI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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